In regards to the draw down phase, I believe Dave may have some of following thoughts in mind (although I hate to make assumptions). I do not know how easy this will be to include in your spread sheet, but if you can, give it a try.

The "withdrawls" from the IUL account will most likely be taken as loans. Most IUL accounts allow you to take the loan at a fixed rate (I think somewhere around 6%). However, for the purpose of index crediting your balance does not decrease. So if you take a withdrawl/loan for a $1000, that $1000 will still be credited at the end of the year along with all your other funds with a gain of between 0 and 12% (the floor and cap). Of course, you have to pay the 6% interest on the loan, so that $1000 loan will result in your account balance decling by up to $60 if the index floor is hit or actually increase your account by up to $60 if the cap is hit.

In addition, loans from IULs are tax free. Depending on where your non-IUL S&P fund is (IRA, 401K, brokerage account, etc) you will be facing anywhere from about 15-40% taxes on withdrawls. So after considering taxes, withdrawing $650 from the IUL may be equivalent to withdrawing $1000 from your retirement account.

Now, I know that most people will would be paying closer to the 15% than the 40%. But, in my opinion, if IULs have a role, it is for high net worth individuals - people who are already maxing out their tax-deferred savings options and saving additional money in non-retirement accounts. These people will likely remain in a high tax bracket after retirement, where marginal rates on income from IRA distributions can be 39%, and even long term capital gains will be 20%.

And speaking of taxes, what about the taxes on the dividends that are being received from the S&P index? As of this year, they could be taxed at 20% (during the period of your test data, there were times when the taxes could have been significantly higher). Lastly, your SMA strategy would regularly be incuring captial gains taxes that would lower its overall performance.

I know the inclusion of taxes is difficult and obviously varies significantly from one individual to the next. But as I said earlier, if there is a role for IULs I suspect it is for those individuals in the top tax brackets.